DT_Var.py
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上传日期:2007-01-04
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- ##############################################################################
- #
- # Zope Public License (ZPL) Version 1.0
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- ##############################################################################
- __doc__='''Variable insertion parameters
- When inserting variables, parameters may be specified to
- control how the data will be formatted. In HTML source, the
- 'fmt' parameter is used to specify a C-style or custom format
- to be used when inserting an object. In EPFS source, the 'fmt'
- parameter is only used for custom formats, a C-style format is
- specified after the closing parenthesis.
- Custom formats
- A custom format is used when outputing user-defined
- objects. The value of a custom format is a method name to
- be invoked on the object being inserted. The method should
- return an object that, when converted to a string, yields
- the desired text. For example, the HTML source::
- <!--#var date fmt=DayOfWeek-->
- Inserts the result of calling the method 'DayOfWeek' of the
- object bound to the variable 'date', with no arguments.
- In addition to object methods, serveral additional custom
- formats are available:
- 'whole-dollars' -- Show a numeric value with a dollar symbol.
- 'dollars-and-cents' -- Show a numeric value with a dollar
- symbol and two decimal places.
- 'collection-length' -- Get the length of a collection of objects.
- Note that when using the EPFS source format, both a
- C-style and a custom format may be provided. In this case,
- the C-Style format is applied to the result of calling
- the custom formatting method.
- Null values and missing variables
- In some applications, and especially in database applications,
- data variables may alternate between "good" and "null" or
- "missing" values. A format that is used for good values may be
- inappropriate for null values. For this reason, the 'null'
- parameter can be used to specify text to be used for null
- values. Null values are defined as values that:
- - Cannot be formatted with the specified format, and
- - Are either the special Python value 'None' or
- are false and yield an empty string when converted to
- a string.
- For example, when showing a monitary value retrieved from a
- database that is either a number or a missing value, the
- following variable insertion might be used::
- <dtml-var cost fmt="$%.2d" null='n/a'>
- Missing values are providing for variables which are not
- present in the name space, rather than raising an NameError,
- you could do this:
- <dtml-var cost missing=0>
- and in this case, if cost was missing, it would be set to 0.
- In the case where you want to deal with both at the same time,
- you can use 'default':
- <dtml-var description default=''>
- In this case, it would use '' if the value was null or if the
- variable was missing.
- String manipulation
- A number of special attributes are provided to transform the
- value after formatting has been applied. These parameters
- are supplied without arguments.
- 'lower' -- cause all upper-case letters to be converted to lower case.
- 'upper' -- cause all upper-case letters to be converted to lower case.
- 'capitalize' -- cause the first character of the inserted value
- to be converted to upper case.
- 'spacify' -- cause underscores in the inserted value to be
- converted to spaces.
- 'thousands_commas' -- cause commas to be inserted every three
- digits to the left of a decimal point in values containing
- numbers. For example, the value, "12000 widgets" becomes
- "12,000 widgets".
- 'html_quote' -- convert characters that have special meaning
- in HTML to HTML character entities.
- 'url_quote' -- convert characters that have special meaning
- in URLS to HTML character entities using decimal values.
- 'url_quote_plus' -- like url_quote but also replace blank
- space characters with '+'. This is needed for building
- query strings in some cases.
- 'sql_quote' -- Convert single quotes to pairs of single
- quotes. This is needed to safely include values in
- Standard Query Language (SQL) strings.
- 'newline_to_br' -- Convert newlines and carriage-return and
- newline combinations to break tags.
- 'url' -- Get the absolute URL of the object by calling it's
- 'absolute_url' method, if it has one.
- Truncation
- The attributes 'size' and 'etc' can be used to truncate long
- strings. If the 'size' attribute is specified, the string to
- be inserted is truncated at the given length. If a space
- occurs in the second half of the truncated string, then the
- string is further truncated to the right-most space. After
- truncation, the value given for the 'etc' attribute is added to
- the string. If the 'etc' attribute is not provided, then '...'
- is used. For example, if the value of spam is
- '"blah blah blah blah"', then the tag
- '<!--#var spam size=10-->' inserts '"blah blah ..."'.
- Evaluating expressions without rendering results
- A 'call' tag is provided for evaluating named objects or expressions
- without rendering the result.
-
- ''' # '
- __rcs_id__='$Id: DT_Var.py,v 1.34.4.1 1999/12/13 18:14:51 jim Exp $'
- __version__='$Revision: 1.34.4.1 $'[11:-2]
- from DT_Util import parse_params, name_param, html_quote, str
- import regex, string, sys, regex
- from string import find, split, join, atoi, rfind
- from urllib import quote, quote_plus
- class Var:
- name='var'
- expr=None
- def __init__(self, args, fmt='s'):
- if args[:4]=='var ': args=args[4:]
- args = parse_params(args, name='', lower=1, upper=1, expr='',
- capitalize=1, spacify=1, null='', fmt='s',
- size=0, etc='...', thousands_commas=1,
- html_quote=1, url_quote=1, sql_quote=1,
- url_quote_plus=1, missing='',
- newline_to_br=1, url=1)
- self.args=args
-
- self.modifiers=tuple(
- map(lambda t: t[1],
- filter(lambda m, args=args, used=args.has_key:
- used(m[0]) and args[m[0]],
- modifiers)))
- name, expr = name_param(args,'var',1)
- self.__name__, self.expr = name, expr
- self.fmt = fmt
- if len(args)==1 and fmt=='s':
- if expr is None: expr=name
- else: expr=expr.eval
- self.simple_form=expr,
- def render(self, md):
- args=self.args
- have_arg=args.has_key
- name=self.__name__
- val=self.expr
- if val is None:
- if md.has_key(name):
- if have_arg('url'):
- val=md.getitem(name,0)
- val=val.absolute_url()
- else:
- val = md[name]
- else:
- if have_arg('missing'):
- return args['missing']
- else:
- raise KeyError, name
- else:
- val=val.eval(md)
- if have_arg('url'): val=val.absolute_url()
- __traceback_info__=name, val, args
- if val is None and have_arg('null'):
- # Treat None as special case wrt null
- return args['null']
-
- # handle special formats defined using fmt= first
- if have_arg('fmt'):
- fmt=args['fmt']
- if have_arg('null') and not val and val != 0:
- try:
- if hasattr(val, fmt):
- val = getattr(val,fmt)()
- elif special_formats.has_key(fmt):
- val = special_formats[fmt](val, name, md)
- elif fmt=='': val=''
- else: val = fmt % val
- except:
- t, v= sys.exc_type, sys.exc_value
- if hasattr(sys, 'exc_info'): t, v = sys.exc_info()[:2]
- if val is None or not str(val): return args['null']
- raise t, v
- else:
- # We duplicate the code here to avoid exception handler
- # which tends to screw up stack or leak
- if hasattr(val, fmt):
- val = getattr(val,fmt)()
- elif special_formats.has_key(fmt):
- val = special_formats[fmt](val, name, md)
- elif fmt=='': val=''
- else: val = fmt % val
- # finally, pump it through the actual string format...
- fmt=self.fmt
- if fmt=='s': val=str(val)
- else: val = ('%'+self.fmt) % (val,)
- # next, look for upper, lower, etc
- for f in self.modifiers: val=f(val)
- if have_arg('size'):
- size=args['size']
- try: size=atoi(size)
- except: raise 'Document Error',(
- '''a <code>size</code> attribute was used in a <code>var</code>
- tag with a non-integer value.''')
- if len(val) > size:
- val=val[:size]
- l=rfind(val,' ')
- if l > size/2:
- val=val[:l+1]
- if have_arg('etc'): l=args['etc']
- else: l='...'
- val=val+l
- return val
- __call__=render
- class Call:
- name='call'
- expr=None
- def __init__(self, args):
- args = parse_params(args, name='', expr='')
- name, expr = name_param(args,'call',1)
- if expr is None: expr=name
- else: expr=expr.eval
- self.simple_form=expr,None
- def url_quote(v, name='(Unknown name)', md={}):
- return quote(str(v))
- def url_quote_plus(v, name='(Unknown name)', md={}):
- return quote_plus(str(v))
- def newline_to_br(v, name='(Unknown name)', md={}):
- v=str(v)
- if find(v,'r') >= 0: v=join(split(v,'r'),'')
- if find(v,'n') >= 0: v=join(split(v,'n'),'<br>n')
- return v
- def whole_dollars(v, name='(Unknown name)', md={}):
- try: return "$%d" % v
- except: return ''
- def dollars_and_cents(v, name='(Unknown name)', md={}):
- try: return "$%.2f" % v
- except: return ''
- def thousands_commas(v, name='(Unknown name)', md={},
- thou=regex.compile(
- "([0-9])([0-9][0-9][0-9]([,.]|$))").search):
- v=str(v)
- vl=split(v,'.')
- if not vl: return v
- v=vl[0]
- del vl[0]
- if vl: s='.'+join(vl,'.')
- else: s=''
- l=thou(v)
- while l >= 0:
- v=v[:l+1]+','+v[l+1:]
- l=thou(v)
- return v+s
-
- def whole_dollars_with_commas(v, name='(Unknown name)', md={}):
- try: v= "$%d" % v
- except: v=''
- return thousands_commas(v)
- def dollars_and_cents_with_commas(v, name='(Unknown name)', md={}):
- try: v= "$%.2f" % v
- except: v= ''
- return thousands_commas(v)
- def len_format(v, name='(Unknown name)', md={}):
- return str(len(v))
- def len_comma(v, name='(Unknown name)', md={}):
- return thousands_commas(str(len(v)))
- StructuredText=None
- def structured_text(v, name='(Unknown name)', md={}):
- global StructuredText
- if StructuredText is None: import StructuredText
- return str(StructuredText.html_with_references(str(v), 3))
- def sql_quote(v, name='(Unknown name)', md={}):
- """Quote single quotes in a string by doubling them.
- This is needed to securely insert values into sql
- string literals in templates that generate sql.
- """
- if find(v,"'") >= 0: return join(split(v,"'"),"''")
- return v
- special_formats={
- 'whole-dollars': whole_dollars,
- 'dollars-and-cents': dollars_and_cents,
- 'collection-length': len_format,
- 'structured-text': structured_text,
- # The rest are depricated:
- 'sql-quote': sql_quote,
- 'html-quote': html_quote,
- 'url-quote': url_quote,
- 'url-quote-plus': url_quote_plus,
- 'multi-line': newline_to_br,
- 'comma-numeric': thousands_commas,
- 'dollars-with-commas': whole_dollars_with_commas,
- 'dollars-and-cents-with-commas': dollars_and_cents_with_commas,
- }
- def spacify(val):
- if find(val,'_') >= 0: val=join(split(val,'_'))
- return val
- modifiers=(html_quote, url_quote, url_quote_plus, newline_to_br,
- string.lower, string.upper, string.capitalize, spacify,
- thousands_commas, sql_quote)
- modifiers=map(lambda f: (f.__name__, f), modifiers)
- class Comment:
- '''Comments
- The 'comment' tag can be used to simply include comments
- in DTML source.
-
- For example::
-
- <!--#comment-->
-
- This text is not rendered.
- <!--#/comment-->
- '''
- name='comment'
- blockContinuations=()
- def __init__(self, args, fmt=''): pass
- def render(self, md):
- return ''
- __call__=render